This application claims priority to provisional U.S. Application Ser. No. 60/269,354, entitled “Enhanced Channel Access Mechanisms For A QoS-Driven HPNA Network,” invented by Wei Lin and Matthew Sherman, filed Feb. 20, 2001, and provisional U.S. Application Ser. No. 60/269,861, entitled HPNA 3.0 channel access mechanism for compatibility with HPNA 2, invented by Matthew J. Sherman, filed Feb. 21, 2001, both of which are incorporated by reference herein. The present application is also related to U.S. patent application Ser. Nos. 10/042,165, 10/042,179, 10/042,166, and 10/042,143, each entitled “Enhanced Channel Access Mechanism For QoS-Driven HomePNA (HPNA 2.1), each filed on Dec. 19, 2001, and each incorporated by reference herein.